PITTSBURGH — Workers approved a four-year labor contract with Goodyear Tire & Rubber Co. that affects about 8,000 employees at six U.S. plants and protects against closures at those facilities, union officials said Thursday.

The union said that steelworkers passed the contract by a 3-to-1 margin.

While discussing Goodyear's second-quarter earnings, which beat expectations, chairman and CEO Richard Kramer indicated that the tentative agreement with the union would help the company's competitive position.

"We believe we will be able to sustain our competitive position and be ready to take advantage of opportunities when demand begins to accelerate," he said.

The tire industry has been aided by a revived American auto industry, which had its best performance in five years in 2012. The United Steelworkers acknowledged that link and had indicated that wages, health care and pensions topped the list of issues at the bargaining table.

The union and Akron, Ohio-based Goodyear began contract negotiations in the spring with the backdrop of an uncertain economy, shrinking unions and company cost-cutting. They reached the agreement on July 27 to avoid a strike hours before a deadline.